1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10
11// <mdspan>
12
13// template<class OtherExtents>
14// constexpr explicit(!is_convertible_v<OtherExtents, extents_type>)
15// mapping(const mapping<OtherExtents>&) noexcept;
16
17// Constraints: is_constructible_v<extents_type, OtherExtents> is true.
18//
19// Preconditions: other.required_span_size() is representable as a value of type index_type
20
21#include <cassert>
22#include <cstddef>
23#include <limits>
24#include <mdspan>
25#include <type_traits>
26
27#include "test_macros.h"
28
29template <class To, class From>
30constexpr void test_implicit_conversion(To dest, From src) {
31 assert(dest == src);
32}
33
34template <bool implicit, class ToE, class FromE>
35constexpr void test_conversion(FromE src_exts) {
36 using To = std::layout_left::mapping<ToE>;
37 using From = std::layout_left::mapping<FromE>;
38 From src(src_exts);
39
40 ASSERT_NOEXCEPT(To(src));
41 To dest(src);
42
43 assert(dest == src);
44 if constexpr (implicit) {
45 dest = src;
46 assert(dest == src);
47 test_implicit_conversion<To, From>(src, src);
48 }
49}
50
51template <class T1, class T2>
52constexpr void test_conversion() {
53 constexpr size_t D = std::dynamic_extent;
54 constexpr bool idx_convertible =
55 static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
56
57 // clang-format off
58 test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>());
59 test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5));
60 test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
61 test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>());
62 test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));
63 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));
64 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));
65 test_conversion<idx_convertible && true, std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());
66 test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));
67 test_conversion<idx_convertible && true, std::extents<T1, D, D, D, D, D>>(
68 std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));
69 test_conversion<idx_convertible && true, std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));
70 test_conversion<idx_convertible && true, std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());
71 // clang-format on
72}
73
74template <class IdxT, size_t... Extents>
75using mapping_t = std::layout_left::mapping<std::extents<IdxT, Extents...>>;
76
77constexpr void test_no_implicit_conversion() {
78 constexpr size_t D = std::dynamic_extent;
79
80 // Sanity check that one static to dynamic conversion works
81 static_assert(std::is_constructible_v<mapping_t<int, D>, mapping_t<int, 5>>);
82 static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<int, D>>);
83
84 // Check that dynamic to static conversion only works explicitly
85 static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, D>>);
86 static_assert(!std::is_convertible_v<mapping_t<int, D>, mapping_t<int, 5>>);
87
88 // Sanity check that one static to dynamic conversion works
89 static_assert(std::is_constructible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
90 static_assert(std::is_convertible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
91
92 // Check that dynamic to static conversion only works explicitly
93 static_assert(std::is_constructible_v<mapping_t<int, 5, 7>, mapping_t<int, D, 7>>);
94 static_assert(!std::is_convertible_v<mapping_t<int, D, 7>, mapping_t<int, 5, 7>>);
95
96 // Sanity check that smaller index_type to larger index_type conversion works
97 static_assert(std::is_constructible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
98 static_assert(std::is_convertible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
99
100 // Check that larger index_type to smaller index_type conversion works explicitly only
101 static_assert(std::is_constructible_v<mapping_t<int, 5>, mapping_t<size_t, 5>>);
102 static_assert(!std::is_convertible_v<mapping_t<size_t, 5>, mapping_t<int, 5>>);
103}
104
105constexpr void test_rank_mismatch() {
106 constexpr size_t D = std::dynamic_extent;
107
108 static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int>>);
109 static_assert(!std::is_constructible_v<mapping_t<int>, mapping_t<int, D, D>>);
110 static_assert(!std::is_constructible_v<mapping_t<int, D>, mapping_t<int, D, D>>);
111 static_assert(!std::is_constructible_v<mapping_t<int, D, D, D>, mapping_t<int, D, D>>);
112}
113
114constexpr void test_static_extent_mismatch() {
115 constexpr size_t D = std::dynamic_extent;
116
117 static_assert(!std::is_constructible_v<mapping_t<int, D, 5>, mapping_t<int, D, 4>>);
118 static_assert(!std::is_constructible_v<mapping_t<int, 5>, mapping_t<int, 4>>);
119 static_assert(!std::is_constructible_v<mapping_t<int, 5, D>, mapping_t<int, 4, D>>);
120}
121
122constexpr bool test() {
123 test_conversion<int, int>();
124 test_conversion<int, size_t>();
125 test_conversion<size_t, int>();
126 test_conversion<size_t, long>();
127 test_no_implicit_conversion();
128 test_rank_mismatch();
129 test_static_extent_mismatch();
130 return true;
131}
132
133int main(int, char**) {
134 test();
135 static_assert(test());
136 return 0;
137}
138

source code of libcxx/test/std/containers/views/mdspan/layout_left/ctor.mapping.pass.cpp